Non-mechanical tracking devices, such as computer mice, are rapidly growing in popularity worldwide. Many of these non-mechanical tracking devices utilize optical navigation technology that measures the changes in position of the non-mechanical tracking devices by optically acquiring sequential surface images and mathematically determining the direction and magnitude of the movement.
As an example, in a non-mechanical tracking device such as an optical mouse, optical navigation technology involves capturing an image and then analyzing and tracking the motion of microscopic texture or other features on a surface under the optical mouse. In general, these types of optical mice depend on tracking surface detail and require work surfaces that are microscopically textured. When such surface textures are illuminated by a light source such as a light emitting diode (“LED”), a pattern of highlights and shadows is revealed. Optical mice then “watch” these surface details move by imaging them onto navigation integrated circuits (“navigation ICs”).
As an example, in FIG. 1, a block diagram 100 of an example of a known implementation of an optical navigation device 102 above a navigation surface 104 is shown. The optical navigation device 102 may be a non-mechanical tracking device such as an optical mouse. Generally, optical navigation technology involves capturing an image on the navigation surface 104 and then analyzing and tracking the motion of microscopic texture or other features on the navigation surface 104 under the optical navigation device 102.
In an example of operation, these surface textures are illuminated by a light source such as an LED in an emitter module 106 that may emit emitted optical radiation 108 at the navigation surface 104, and a pattern of highlights and shadows is revealed at a point of illumination 110 on the navigation surface 104. The optical navigation device 102 then “watches” the surface details of the navigation surface 104 move by receiving reflected optical radiation 112 from the navigation surface 104 details at the point of illumination 110 at a detector module 114 in the optical navigation device 102. The detector module 114 may be part of a navigation integrated circuit (“IC”) 116 located within the optical navigation device 102. The navigation IC 116 may also include a navigation engine 118 where the navigation engine 118 is a device capable of receiving imaging information from the detector module 114 and, in response, determining the position of the optical navigation device 102.
Unfortunately, although widely used as computer input devices, optical navigation devices such as the non-mechanical device 100 have not been widely used in many other applications. This is due primarily to the fixed operating Z-height of these devices, as well as the large form factor, i.e., footprint, of these devices. FIG. 2 shows a cross-sectional side view of a typical optical mouse sensor 200, with an optical sensor 202 attached to lens 206, sometimes with a clip (not shown). In an example of operation, a light emitting diode (“LED”) illuminator source (not shown) emits light that is reflected from the navigation surface 204. In this particular device, the Z-height 208, which is the distance from the lens reference plane to the navigation surface 204, may typically be 2.4 millimeters (“mm”), ±0.1 mm, and is fixed at that dimension. A typical mouse device may also have, for example, a form factor of approximately 10.0 mm×12.5 mm.
Because optical navigation devices with an adjustable operating Z-height and a smaller form factor would find usage in many more additional applications, there is a need for such an optical navigation system having a non-fixed or adjustable Z-height and a smaller form factor.